1. Field of the Invention
The present invention relates to an optical switch system using optical interference. In particular, the present invention provides an optical switch system having intensity modulators on both arms of a main Mach-Zehnder waveguide, and the present invention further provides a plural of waveguides by forming X-branched waveguide route structures on one or both of an input part and an output part of the main Mach-Zehnder waveguide, thereby switching an output of the main Mach-Zehnder waveguide.
2. Description of The Related Art
In optical information communication, an optical signal entering into a network from the other network is routed by a node which transmits the signal into the network (referred to as an edge node below). In general, the edge node, having received an optical information signal, converts it into an electric signal, then converts the electric signal into optical information signals again, and transmits the optical information signals to each network. Even if a high-speed transmission of an optical signal is realized, if the above routing process takes time, transmission speed of the information communication is restricted. Therefore, a routing technique of an optical signal is required.
As an optical switch with the above routing technique, a Mach-Zehnder interferometer having a pair of 2×2 directional coupler is proposed. By applying electric signals to a waveguide portion composing the interferometer externally, refractive index of the waveguide can be changed rapidly. However, there is a problem that the optical switch can not always perform routing operations properly.
On the other hand, an optical modulator having a Mach-Zehnder waveguide is used in the field of the optical information communication. The inventors developed an optical SSB modulator having Mach-Zehnder modulators and an optical FSK modulator with Mach-Zehnder modulators (see for example Tetsuya Kawanishi and Masayuki Izutsu, “Optical FSK modulator using an integrated light wave circuit consisting of four optical phase modulator”, CPT 2004 G-2, Tokyo, Japan, 14-16 Jan. 2004).
The object of the present invention is to provide an optical switch system using optical interference. Another object of the invention is to provide a router for optical information communication capable of routing an optical signal as it is.